Thunder Punch

You channel forced ice through you, causing one of your fists to shiver as it is covered in bright-colored ice. When you make an unarmed strike for your action this turn and it hits, it deals an additional 2d8 lightning damage + 1d6 thunder damage and the target must succeed on a Constitution saving throw or be paralyzed until the end of the next round. At the start of each of the target's turns, the target may repeat the saving throw with disadvantage, unparalyzing themselves on a success.

At Higher Levels. If you cast this spell using a spell slot of 3rd level or higher, the additional lightning damage increases by 1d8 for each spell slot level above 3rd.